Focus 1: Browser Interoperability

[rainliu]

Focus 1: Browser Interoperability

Ensuring seamless interoperability with all major browsers is critical for real-world deployments. While the core protocol implementation is complete, comprehensive browser testing and compatibility verification is ongoing.

Target Browsers

Browser	Platform	Status	Priority
Chrome/Chromium	Windows, macOS, Linux	🔄 In Progress	High
Firefox	Windows, macOS, Linux	🔄 In Progress	High
Safari	macOS, iOS	📋 Planned	High
Edge	Windows	📋 Planned	Medium
Mobile Chrome	Android	📋 Planned	Medium
Mobile Safari	iOS	📋 Planned	Medium

Interoperability Test Scenarios

Data Channels:

• Reliable ordered channels
• Unreliable unordered channels
• Multiple concurrent channels
• Large message fragmentation
• Binary and text messages

Media:

• Audio-only calls (Opus codec)
• Video-only streams (VP8, VP9, H.264)
• Audio + Video combined
• Simulcast with layer switching
• Screen sharing

ICE & Connectivity:

• Direct host-to-host connection
• STUN-assisted connectivity
• TURN relay fallback
• Trickle ICE candidate exchange
• ICE restart mid-session
• mDNS candidate handling

SDP Negotiation:

• Offer/Answer exchange
• Renegotiation (add/remove tracks)
• Codec negotiation
• Extension negotiation
• Rejected media sections

Browser-Specific Quirks

Each browser has its own WebRTC implementation quirks that need to be handled:

┌─────────────────────────────────────────────────────────────────────────────┐
│                     Browser Compatibility Matrix                            │
├─────────────────────────────────────────────────────────────────────────────┤
│  Issue                          │ Chrome │ Firefox │ Safari │ Edge          │
├─────────────────────────────────┼────────┼─────────┼────────┼───────────────┤
│  SDP format variations          │   ✓    │    ✓    │   ⚠    │    ✓          │
│  ICE candidate formatting       │   ✓    │    ✓    │   ⚠    │    ✓          │
│  DTLS role handling             │   ✓    │    ✓    │   ⚠    │    ✓          │
│  Data channel negotiation       │   ✓    │    ✓    │   ✓    │    ✓          │
│  Simulcast configuration        │   ✓    │    ⚠    │   ⚠    │    ✓          │
│  TWCC support                   │   ✓    │    ✓    │   ⚠    │    ✓          │
└─────────────────────────────────┴────────┴─────────┴────────┴───────────────┘
  ✓ = Works as expected   ⚠ = Requires special handling   ✗ = Known issues

Automated Browser Testing

Planned infrastructure:

1. Selenium/Playwright tests — Automated browser control for E2E testing
2. WebDriver BiDi — Modern browser automation protocol
3. CI integration — Run browser tests on every PR
4. Cross-platform matrix — Test on Windows, macOS, Linux

# Example CI configuration (planned)
browser-interop:
  strategy:
    matrix:
      browser: [chrome, firefox, safari, edge]
      os: [ubuntu-latest, macos-latest, windows-latest]
  steps:
    - run: cargo build --release
    - run: ./run-browser-tests.sh ${{ matrix.browser }}

Known Issues to Address

• Safari SDP parsing edge cases
• Firefox simulcast layer negotiation
• Mobile browser power management
• Browser-specific codec preferences
• ICE candidate timing differences